EGU General Assembly 2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

Assessing the long-term physical-biogeochemical interactions in the North Indian Ocean using a coupled relocatable model

Jenny Jardine1, Anna Katavouta1, Dale Partridge2, Jeff Polton1, Jason Holt1, and Sarah Wakelin1
Jenny Jardine et al.
  • 1National Oceanography Centre, Marine System Modelling , United Kingdom of Great Britain – England, Scotland, Wales (
  • 2Plymouth Marine Laboratory, Plymouth, United Kingdom

The Indian Ocean is a dynamic region that is heavily influenced by immense freshwater runoff, extreme meteorological events and the seasonal reversal of monsoonal currents. Providing essential resources for over one-third of the global population, the Northern Indian Ocean is a key area of research: increased freshwater run-off, low overturning velocities and high air-sea fluxes result in the region being highly susceptible to climate fluctuations, and execess nutrients, particularly nitrates accumulated through agricultural run-off, directly influence marine biogeochemical cycles. The South Asia Nitrogen Hub (SANH) is a GCRF project designed to assess, monitor and predict the physical and biogeochemical response of the Northern Indian Ocean to such anthropogenic changes. To address key questions in SANH, a relocatable physical-biogeochemical (NEMO-ERSEM) was configured across the region, which includes the Eastern Arabian Sea and the Bay of Bengal. A 22-year hindcast run (1993-2015) at ~11km resolution allows the physical-biogeochemical processes (including from mesoscale eddies, extreme meteorological events and varying runoff) to be viewed at scale that is otherwise impossible with observational campaigns. In conjunction with the large-scale model domain, 6 smaller high-resolution (~1-2km) coastal models were configurated around the Indian subcontinent, allowing a more focussed view at processes that directly impact coastal populations. Here, we will present initial results from the large-scale hindcast run, the coastal regions, and explore the advantages and caveats of relocatable modelling.

How to cite: Jardine, J., Katavouta, A., Partridge, D., Polton, J., Holt, J., and Wakelin, S.: Assessing the long-term physical-biogeochemical interactions in the North Indian Ocean using a coupled relocatable model, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-9706,, 2021.


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